RU107441U1 - DEVICE FOR IGNITION OF DISCHARGE LAMPS - Google Patents

Abstract

 A device for igniting gas discharge lamps powered from an alternating current main through a current limiter, comprising a working capacitor charged through a current-limiting element from the mains through a current limiter, connected via a switching element unlocked from a control unit parallel to the primary winding of a pulse transformer, the secondary winding of which is connected in series with the lamp, the switching element is made in the form of a rectifier bridge with a transistor in the diagonal, unlocked by the control unit for a period of 1 -100 μs, characterized in that a second control unit is additionally introduced, connected in parallel with the first control unit and unlocking the transistor for a time of 10-1000 μs with subsequent unlocking of the transistor by the first control unit after a time interval of 10-100 μs at least once per network period voltage.

Description

The utility model relates to electrical engineering and can be used to ignite discharge lamps.

A device is known for igniting gas discharge lamps fed directly from an alternating current network or through a current limiter, comprising a working capacitor charged via a current-limiting element directly from the network or through a current limiter, connected via a switching element unlocked from a control unit parallel to the primary winding of a pulse transformer, the secondary winding of which connected in series with the lamp, the switching element is made in the form of a rectifier bridge with a transistor in the diagonal of the unlocked control unit for a time of 1 μs - 100 μs when the voltage at the working capacitor reaches 0.5-1.0 of the amplitude value of the mains voltage at least once during a period of mains voltage. (RU No. 2254693 class. Н05В 41/23, 11/18/2002),

When the transistor is turned on, the device generates a high-voltage pulse, ionizing gas filling the lamp. However, non-stationary processes accompanying the generation of a high-voltage pulse lead to the fact that the current in the drosel-llama circuit, when used as a current limiter of the inductor, increases slowly, which does not maintain the current through the lamp after breakdown, reducing the reliability of the device, especially when it is used for ignition of lamps with a short plasma deionization time.

The technical result is to increase the reliability of the device.

The technical result is achieved by the fact that the device contains a working capacitor connected via a switching element, unlocked from the control unit, parallel to the primary winding of a pulse transformer. The switching element is made in the form of a rectifier bridge with a transistor in the diagonal unlocked control unit for a time of 1-100 μs. Additionally, a second control unit has been introduced, connected in parallel with the first control unit and unlocking the transistor for a time of 10-100 μs, followed by the unlocking of the transistor by the first control unit after a time interval of 10-100 μs at least once during a network voltage period.

Figure 1 shows the proposed device for ignition of gas discharge lamps, including a working capacitor 1 connected through a switching element 2, comprising a rectifier bridge with a transistor in the diagonal, unlocked from control units 3 and 4, connected in parallel to each other. In parallel with the primary winding of the pulse transformer 5, control units 3 and 4 are connected. A circuit consisting of series-connected secondary windings of the pulse transformer 5 and lamp 6 is connected to the network through the current limiter 7. The shunt capacitor 8 is connected to the network through the current limiter 7. The working capacitor 1 is connected through a current-limiting element 9 parallel to the shunt capacitor 8.

The device operates as follows. A working capacitor 1 is charged through a current-limiting element 9. As soon as the voltage U on the capacitor 1 reaches a certain value (usually within 0.5-1 of the amplitude value of the mains voltage), the control unit 4 generates a pulse that unlocks the transistor of the switching element 2 for a time of 10-1000 μs. During this time, the current through the current limiter (inductor) 7 rises to a value determined by its inductance, pulse duration, resistance of the current-limiting element 9. After locking the switching element 2, the current through the inductor does not stop, the capacitor 1 is charged. After a time of 10-100 μs, the control unit 3 generates a pulse that unlocks the transistor of the switching element 2 for a time of 1-100 μs. During this time, the working capacitor 1 is discharged through the primary winding of the pulse transformer 5, the secondary winding of which is connected in series with the lamp 6 and the shunt capacitor 8. The emf induced on the secondary winding provides a breakdown of the interelectrode gap of the discharge lamp. Due to the fact that the breakdown of the interelectrode gap of a gas discharge lamp occurs when the current flowing through the inductor is sufficient to maintain a gas discharge in the lamp, the lamp is reliably ignited. After an arc discharge occurs in the lamp, the device turns off.

The choice of limits for the duration of the first pulse is determined by the fact that for a time shorter than 10 μs, the current through the inductor does not reach a value capable of maintaining the current in the lamp immediately after the breakdown. An increase in time of more than 1000 μs is impractical due to excessive heating of the current-limiting element 9.

Reducing the duration of the pause between pulses of less than 10 μs will not provide a sufficient amplitude of the capacitor charge 1 with the current generated by the inductor 7. Increasing the duration of the pause of more than 100 μs will reduce the current through the inductor to a value that is unable to maintain the current in the lamp immediately after the breakdown.

Claims (1)

A device for igniting gas-discharge lamps powered from an alternating current main through a current limiter, comprising a working capacitor charged via a current-limiting element from the mains through a current limiter, connected via a switching element unlocked from a control unit parallel to the primary winding of a pulse transformer, the secondary winding of which is connected in series with the lamp, the switching element is made in the form of a rectifier bridge with a transistor in the diagonal, unlocked by the control unit for a period of 1 -100 μs, characterized in that a second control unit is added, connected in parallel with the first control unit and unlocking the transistor for a time of 10-1000 μs, followed by the unlocking of the transistor by the first control unit after a time interval of 10-100 μs at least once during the network period voltage.